Method and apparatus for mining manganese nodules from the deep sea-bottom

ABSTRACT

A mechanism for mining manganese nodules from the deep sea bottom including a number of dredge nets tied to a long endless rope suspended from both sides of a ship, the rope falling from one side of the ship to the deep sea-bottom with apparatus being provided to pull the rope therefrom to another side of the ship, whereby manganese nodules are continuously collected by the dredge nets.

United States Patent Masuda et a1.

[54] METHOD AND APPARATUS FOR MINING MANGANESE NODULES FROM THE DEEPSEA-BOTTOM [72] Inventors: Yoshio Masuda; Toshikazu Murakami,

both of Tokyo, Japan [22] Filed: April 22, 1970 [21] Appl. No.2 28,287

Related US. Application Data [63] Continuation of Ser. No. 701,739, Jan.30, 1968,

abandoned.

130] Foreign Application Priority Data Feb. 14, 1967 Japan ..42/8979[52] U.S. Cl ..37/69, 37/195, 43/6.5,

[51] Int. Cl. .1502! 3/14 [58] Field 01 Search ..37/69, 60,55, 119;198/116, 198/130,151,14l;43/6.5

[56] References Cited UNITED STATES PATENTS 708,583 9/1902 Powell..37/70 51 June 27, 1972 653,324 7/1900 Stuebner ..198/1 41 X 3,378,1304/1968 Wallace ..37/69 X 3,146,537 9/1964 Von Bolhar. ..37/69 978,96812/1910 Webb ..37/55 X 2,636,288 4/1953 Thomas ..37/69 X FOREIGN PATENTSOR APPLICATIONS 1,000,273 10/ 1 951 France ..37/69 80,446 2/1951 Norway..43/6.5

Primary Examiner-Robert E. Pulfrey Assistant Examiner-Clifford D.Crowder Attorney-Fidelman, Wolffe & Leitner [57] ABSTRACT A mechanismfor mining manganese nodules from the deep sea bottom including a numberof dredge nets tied to a long endless rope suspended from both sides ofa ship, the rope falling from one side of the ship to the deepsea-bottom with apparatus being provided to pull the rope therefrom toanother side of the ship, whereby manganese nodules are continuouslycollected by the dredge nets.

6 Claims, 7 Drawing Figures P'A'TENTEDJUMN I972 susmurs v Fl G.l

F I s P'A'TENTEnJum m2 3.672.079

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METHOD AND APPARATUS FOR MINING MANGANESE NODULES FROM THE DEEPSEA-BOTTOM This application is a continuation of application Ser. No.701,739, filed Jan. 30, 1968, now abandoned.

This invention relates to a mechanism for mining manganese nodules fromthe deep sea-bottom by use of improved dredge nets.

A great amount of manganese nodules containing such elements asmanganese, cobalt, nickel and copper have been found at the deepsea-bottom. These metals are originally contained in seawater andcrystallized on and around fish bones, etc., and form manganese nodules.These manganese nodules lie scattered on the soft clay piled at the deepsea-bottom. Ac cording to the survey conducted by IGY, it has been foundthat approximately 10 percent of sea-bottom area of the Pacific iscovered with manganese nodules. It has also been found that manganesenodules at the sea-bottom of the middle Pacific Ocean contain 31.7percent manganese, 17.5 percent iron, 0.69 percent cobalt, 1.45 percentnickel and 1.09 percent copper. Assuming that such manganese nodules canbe mined from the deep sea-bottom using some mining machines on anindustrial scale, the cost of manganese nodules would be in the range offrom 40 to 100 dollars per ton. The practicality and economy for mininghave been studied and proposed by Mr. Mero in the U.S.A.

According to Mineral Resources of the Sea authored by Mero in 1965,nodules can be mined by ships on the surface of the sea by means of along pipe using suction dredges, but it would be expensive and theventure marginal, considering the difiiculties of operations on the seawith long pipe and underwater pumping machine. This invention, however,does not use such an underwater pump, etc. In this connection, thepresent inventors noticed that Japanese fisherman had used a dredge nethaving combs to collect a large quantity of shells from the sea-bottom,and that such a dredge net would be use ful for collecting manganesenodules from the sea-bottom. Since a hundred years ago, many explorershave collected manganese nodules using dredge nets drawn by a long ropefrom ships stern. It, however, takes a long time to lower the rope downand to pull it up from the deep sea-bottom. Therefore, the dredge nethas been considered unpractical for the reason of slow production speed.However, the inventors, restings on a conviction that a dredge net isthe only means which can collect manganese nodules, have studied theimprovement in the dredge net system, i.e., on the possibility ofincreasing the production speed of manganese nodules by means of dredgenet, and thus attained the present invention.

It is, therefore, an object of the present invention to provide animproved dredge net capable of increasing the production speed ofmanganese nodules.

The nature, principle, details and utility of the invention will be moreclearly apparent from the following detailed description with respect toa preferred embodiment of the invention when read in conjunction withaccompanying drawings, in which:

FIG. I is a side view of a mechanism for mining manganese nodules at thedeep sea-bottom embodying the present invention;

FIG. 2 is a cross sectional view of a stern of a mining ship;

FIG. 3 is a perspective view showing one mode of the mechanism tested ina water tank;

FIG. 4 is a perspective view showing a tangled rope;

FIG. 5 is a perspective view showing the movement of rope and dredgeweight at the tank's bottom;

FIG. 6 is a perspective view showing the mining ship equipped with themining mechanism according to the present invention; and

FIG. 7 is a perspective view showing the dredge net.

FIG. 1 illustrates the general arrangement of the mechanism andaccording to the present invention, in which a mining ship 1 has a frontwheel 2 at a position close to the bow and a rear wheel 3 at a positionclose to the stern, guide wheels 4,5, 6, 7, 8, l and 11 on the deck.Guide plates 12, 13 are respectively attached closely to said guidewheels and 7. Guide rollers 14 is disposed between guide wheels 4 and 5and guide rollers 15 between guide wheels 9 and 10. Along endless rope16 extending from the bow to the deep sea-bottom by way of the sternpasses through the rear wheel 3, guide wheels 4, 5, 6, 7, 8, 9, 10, 11and the front wheel 2, the length of the rope being 2.4 times as long asthe depth of the sea.

A number of dredge nets 17 are tied or secured in any suitable manner tothe long rope 16 at regular intervals. Guide wheels 4, 5, 6, 7, 8, 9, l0and 11 have electrically driven motors incorporated therein. According ythe long rope 16 travels from the bow to the stern by way of thesea-bottom. The arrow 18 indicates the movement direction of the forwardend of the rope and arrow 19 indicates that of the rear end of the rope.The mining ship makes headway at a slow speed. The arrow 20 indicatesthe direction of the ships movement. When the speed of rope is almostequivalent to that of the ship, the forward end of the rope is suspendedalmost perpendicularly but the rear end thereof is pulled by themovements of the ship so that the dredge nets 17 are drawn on the clayat the deep sea-bottom 21 and collect manganese nodules 22 on the clay,and are pulled up onto the sea surface 23.

Now, referring to FIG. 2, when each dredge net 17 passes through thewheels respectively, the long rope 16 is at the inner side of each wheeland the dredge net at the outer side of each wheel so as to pass aroundeach wheel smoothly, as shown in FIG. 2. The rope-line between wheelsinclines and the dredge net 17 passes around the outer side of the wheelby the force of gravity at the rear wheel 3, guide wheels 4, 6, 8 and 9.The guide rollers 14 and 15 have a number of rollers to move dredge nets17 in a smooth manner, and guide the dredge nets 17 to the outer side ofthe guide wheel 5 and the rear portion of the guide wheel 9.

Guide plates 12 and 13 support the dredge nets as they overturn andmanganese nodules in said dredge nets are dropped onto the ship by theforce of gravity. Collected manganese nodules 24 and 25 are transportedto other places in the ship.

The inventors have tested the above mentioned mechanism using a smallmodel in a water tank having a depth of 6.2 m.

Referring to FIG. 3, a small model ship 26 has a front wheel 27, a rearwheel 28 and roller 29 provided with a small motor 30. A long endlessrope 31 extends from the front wheel 27 to water tank bottom 33 by wayof the rear wheel 28 and the roller 29. The rope 31 has a diameter of1.2 mm, a length of 15 m and small lead weights 32 tied thereto at aregular interval of 11 cm.

The distance between the front wheel 27 and the rear wheel 28 is only 14cm, and the ratio of the distance to the depth of the water tank was 144. In the test within the water tank, two different ropes, i.e., aplaited rope and a three-strand rope were used and the plaited ropeproved a success, but the test using the latter failed because of a ropetangle which occurred, as shown in FIG. 4. Since the plaited rope istorsionally balanced, it is capable of preventing rope tangle betweentwo ropes. When the model ship 26 is manually moved in the directionshown by the arrow 33 in FIG. 3, the long rope 31 moves ahead from thefront wheel 27 but is pulled toward the rear wheel 28 at the same speedas the ships movement by the force of the small motor 30. The rope isvertically suspended at the fall portion 31-A, but it is suspended atthe rise portion 3l-B by forming a suspension curve. The floor portion31-C extends on the floor.

Small lead weights 32 are drawn at the tank bottom with each locus shownby dotted line in FIG. 5, leaving the drawn space 34 on the tank bottom33.

To prevent ropes from tangling each other, the rise portion 31-B must bepulled to a predetermined position against the fall portion 3l-A.

In case this positioning of the rise portion is incorrect, it may causea rope tangle. Therefore, care must be taken in this point by thedesigner and operator of the ship.

In a test on the sea of m depth carried out subsequently to theaforementioned water tank test by the present inventors, a plaited nylonrope having a length of 200 m with 80 small cans attached thereto wasused. A small fishing boat was provided with a front wheel and a rearwheel, the distance between the front wheel and the rear wheel being 3m, and the boat could continuously collect mud from the sea-bottom.

in the mining ship shown in FIG. 6, a line leading from the front wheel2 to the rear wheel 3 is deflected slightly from a line leading from thebow to the stem. The deflection, however, serves for pulling the riseportion of the rope 16 at a predetermined position against the fallportion of the rope 16.

Guide wheels, guide rollers and guide plates are all installed on themining boat 1 and operated by the force of ship engines.

Manganese nodules lie scattered on the soft clay at the deep sea-bottom,so that the dredge nets must collect them with good efficiency. Theshape of dredge nets may be varied depending on the conditions ofmanganese nodules, and the dredge nets may be provided with combs in thevicinity of their mouths.

in FIG. 7, the dredge net 17 has a cylindrical shape and is covered witha wire netting and connected to the long rope 16 at a regular intervaland collects manganese nodules by being drawn on the clay layer. Anadvantage of the cylindrical shape lies in facilitating the handling ofthe dredge net.

When dredge nets 17 each having a diameter of 0.8 m, a length of 1.4 mand weight of 100 kg and being capable of collecting 800 kg of manganesenodules in air by one dredging are employed by being tied to the longrope at the interval of 100 m, the production speed of manganese noduleswill be 500 tons per day.

Presumed that a 10,000-ton mining ship is used, it would be estimatedthat the revenue per year would be 4.5 million dollars.

We claim:

1. Apparatus for deep-sea mining of manganese nodules from the bottom ofthe sea comprising:

a ship traversable on the sea surface,

an endless loop torsionally balanced rope extending from the ship bow,beneath the sea along the sea-bottom, upwardly over the ship stern andextending to the ship bow,

a plurality of nodule collecting members serially located on the rope,

said ship being traversable on the sea surface, the traversing motion ofthe ship dragging the nodule collecting members along the sea-bottomcollecting manganese nodules therein,

means on said ship and engaging the endless line for conveying thenodule collecting members containing collected nodules therein from thesea-bottom to the ship stem, and for continuously passing said membersto the bow of said ship, from the bow of said ship to the sea-bottom,resting said members on the sea-bottom and subsequently dragging saidmembers prior to conveying to said ship, and

emptying means for emptying the nodule collecting members containingcollected nodules.

2. The apparatus of claim 1 wherein said nodule collecting members aredredge nets.

3. The structure as recited in claim 1, wherein, said emptying meansincludes a plurality of rollers, said endless loop rope being trained totravel over the circulated peripheries of said rollers, and at least oneof said rollers being elevated with respect to other of said rollers,said nodule collecting members being conveyed by said endless loop lineover the surface of the elevated roller to an inverted condition,whereby the nodules collected therein are emptied.

4. An apparatus as recited in claim 1 wherein said endless rope isadapted to have a length approximately two-four times the depth of seain which the system is being employed.

5. A method for deep-sea mining of manganese nodules from the bottom ofthe sea comprising the steps of:

traversing a ship over the sea surface, urging travel of an endless loopline having a plurality of nodule collecting members serially locatedthereon in a direction from the ship bow downward to the sea-bottom,resting said members on the sea-bottom, subsequently dragging the nodulecollecting members along the seabottom, raising said members to thestern of said ship, emptying the nodule collecting members of thenodules collected therein as the continuous loop line travels from theship bow to the ship stern, and passing said members to the bow of theship for return to the sea-bottom.

6. The method of claim 5 wherein the speed of the ship traversing thesea surface is substantially equal to the travel of the endless loop.

2. The apparatus of claim 1 wherein said nodule collecting members are dredge nets.
 3. The structure as recited in claim 1, wherein, said emptying means includes a plurality of rollers, said endless loop rope being trained to travel over the circulated peripheries of said rollers, and at least one of said rollers being elevated with respect to other of said rollers, said nodule collecting members being conveyed by said endless loop line over the surface of the elevated roller to an inverted condition, whereby the nodules collected therein are emptied.
 4. An apparatus as recited in claim 1 wherein said endless rope is adapted to have a length approximately two-four times the depth of sea in which the system is being employed.
 5. A method for deep-sea mining of manganese nodules from the bottom of the sea comprising the steps of: traversing a ship over the sea surface, urging travel of an endless loop line having a plurality of nodule collecting members serially located thereon in a direction from the ship bow downward to the sea-bottom, resting said members on the sea-bottom, subsequently dragging the nodule collecting members along the sea-bottom, raising said members to the stern of said ship, emptying the nodule collecting members of the nodules collected therein as the continuous loop line travels from the ship bow to the ship stern, and passing said members to the bow of the ship for return to the sea-bottom.
 6. The method of claim 5 wherein the speed of the ship traversing the sea surface is substantially equal to the travel of the endless loop. 